Washington, D.C - As President Barack Obama prepares to meet with Canadian Prime Minister Stephen Harper on September 16, an international network of environmental groups is sending a strong message to the president that Canada's dirty tar sands oil threatens America's clean energy future.

Obama is under pressure from the Canadian government to accept dirty oil from Alberta's tar sands via a sprawling network of pipelines and refineries in the U.S. Producing oil from tar sands emits three to five times the global warming pollution as conventional oil, requires excessive amounts of energy and fresh water, and destroys huge swaths of boreal forest.

"Allowing tar sands pipelines into this country will undercut President Obama's clean energy agenda," said Sierra Club representative Pat Gallagher. "This project will lock us into a dirty oil infrastructure for years to come."

Groups, including Sierra Club and Natural Resources Defense Council, are concerned that Harper's push for tar sands oil will divert the U.S. just as the nation is taking up the mantle of climate leadership and moving toward a clean energy economy future.

"Tar sands should not be allowed to keep our leaders from moving forward on fighting climate change - especially in the run up to the international climate meeting in Copenhagen," said Susan Casey-Lefkowitz, senior attorney, Natural Resources Defense Council. "Canada should be focused on building strong climate and energy regulations at home rather than trying to undermine emerging U.S. climate and energy efforts."

Leading up to Harper’s visit, environmental groups have conducted a wide variety of outreach, including a drive to have citizens send letters to President Obama urging him to protect America from the massive dirty energy project.